Orthodontic face bow

ABSTRACT

The orthopedic face bow includes an outer bow forming an elongated loop at its central portion. An inner bow has its central portion soldered to a central underside portion of the elongated loop and a center piece having upper and lower channels formed therein is positioned within the elongated loop so that the lower side walls of the lower channel eclipse the soldered connection portion of the inner bow to the outer bow. The floor of the upper channel in turn, defines fulcrum surfaces to distribute stresses in cooperation with the end loop portions when the extending ends of the outer bow are bent inwardly.

United States Patent 11 1 Chittenden ORTHODONTIC FACE BOW [76] Inventor:Donald F. Chittenden, 1365 N.

Armel Dr., Covina, Calif. 91722 22 Filed: Apr. 18, 1974 21 Appl. No.:461,855

[52] U.S. Cl 32/14 D [51] Int. Cl. A6lc 7/00 [58] Field of Search 32/14D; 128/146 [56] References Cited UNITED STATES PATENTS 3,137,941 6/1964Andrews 32/14 D 3,311,978 4/1967 Haas et a1. 32/14 D PrimaryExaminer-Robert Peshock Attorney, Agent, or Firm-Pastoriza & Kelly June10, 1975 57 ABSTRACT The orthopedic face bow includes an outer bowforming an elongated loop at its central portion. An inner bow has itscentral portion soldered to a central underside portion of the elongatedloop and a center piece having upper and lower channels formed thereinis positioned within the elongated loop so that the lower side walls ofthe lower channel eclipse the soldered connection portion of the innerbow to the outer bow. The floor of the upper channel in turn, definesfulcrum surfaces to distribute stresses in cooperation with the end loopportions when the extending ends of the outer bow are bent inwardly.

7 Claims, 5 Drawing Figures ORTHODONTIC FACE BOW This invention relatesgenerally to orthodontic devices and more particularly to an improvedface bow construction.

BACKGROUND OF THE INVENTION Conventional prior art face bows normallyinclude an outer bow and an inner bow of lesser radius of curvaturehaving its central portion fixed to the central portion of the outerbow. The inner bow is positioned about a patients teeth in his mouth andengages the patients posterior molars. The outer bow, in turn. passesabout opposite sides of the patients face and terminates in hookportions for receiving some type of force supplying means such as anelastic band. The arrangement is such as to exert inward pressure on theinner end portions of the inner bow to urge the patients teeth in arearward direction. These devices are sometimes referred to as dentalretractors.

A major problem encountered with such appliances is the tendency for theouter bow to break off from the inner bow or in itself fracture as aconsequence of constant flexing or inward bending of the outer ends.Normally. the central portion of the inner bow is silversoldered to thecentral portion of the outer bow and by making a fairly long solderpath, the securement of the members together can be strengthened. On theother hand, the silver-solder itself is unsightly and tarnishes quickly.

Efforts in the past to solve the tendency for the outer bow to break orbecome disconnected from the inner bow have included the formation of aloop in the central portion of the outer bow, curved portions of theloop tending to distribute the stress and thus decreasing the tendencyof breakage under flexing or bending conditions of the outer ends. Withonly a loop portion formed. however, the stress tends to becomeconcentrated at the sharp turn portion of the loop and thus the problemis still present.

Other efforts towards strengthening such appliances have involvedproviding a sheath or surrounding of the connected portions of the innerloop to the outer loop. While such a sheath will strengthen theconnection. stress still is concentrated at the exit points of the outerbow from the sheath. In fact. the stiffening resulting from theprovision ofa surrounding sheath can even aggravate the problem.

In addition to the foregoing. such orthodontic face bows as arepresently available are generally unsightly and uncomfortable for thepatient. A specific problem with respect to discomfort is the sharp andjagged ends of the inner and outer bows which can seriously injure apatient's gums. Moreover. the usual stops provided adjacent to the endsof the inner bows for applying pressure to the patients teeth generallytake the form of solder enlargements wherein again rapid tarnishing ofthe solder takes place and any type of adjustment of the stop positionsis difficult BRIEF DESCRIPTION OF THE PRESENT INVENTION With theforegoing consideration in mind, a basic ob ject of the presentinvention is to provide an improved orthodontic face bow constructionwherein the foregoing problems are substantially overcome.

More particularly, the present invention comprises an outer bow with anelongated loop formed at its central portion. An inner bow in turn hasits central portion secured such as by silver soldering to a centralunderside portion of the elongated loop. A center piece in turn isprovided with upper and lower channels. the lower channel receiving theunderside of the elongated loop and the central portion of the inner bowin a manner such that its lower side walls completely eclipse the silversoldered connection not only inhibiting the tarnishing but alsocontributing towards an esthetic appearance.

The upper channel in turn encompasses in a side-byside relationship theupper portion of the elongated loop and the floor of this upper channeldefines fulcrum surfaces which cooperate with the loops in distributingstress.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing as well as furtherfeatures and advantages of this invention will be understood by nowreferring to a preferred embodiment of the face bow as shown in theaccompanying drawings in which:

FIG. 1 is a perspective view of the orthodontic face bow of thisinvention:

FIG. 2 is an enlarged perspective view of the center piece body onlyutilized in the face bow of FIG. 1;

FIG. 3 is a front elevational view of the face bow looking in thedirection of the arrows 33 of FIG. 1;

FIG. 4 is a plan cross section through the immediate inside wallsurfaces of the center piece taken in the direction of the arrows 4-4 ofFIG. I; and.

FIG. 5 is across section in the direction ofthe arrows 55 of FIG. 1.

DETAILED DESCRlPTlON OF THE PREFERRED EMBODlMENT Referring first to FIG.1, the orthopedic face bow in cludes an outer bow l0 defining anelongated loop 1] at its central portion and terminating at its outerends in integrally formed hooks l2 and 13.

An inner bow member [4 of lesser radius of curvature than the outer howhas a central portion secured to a central underside portion of theelongated loop. This securement will become clearer as the descriptionproceeds. It will be noted that the inner bow member 14 includes halfloops formed near its outer ends as indicated at 15 and 16. These halfloops serve as "stops" in lieu of soldered enlargements or the like ashave characterized prior art devices. The position along the bow atwhich the half loops are formed is selectable thereby enabling the stoppositions to be adjusted. The extreme ends 17 and 18 of the inner how 14as well as the extreme ends of the hooks l2 and [3 on the outer bow 10are all smoothly radiused to avoid the presence of any sharp. jaggedpoints.

The assembly is completed by the provision of a center piece 19 whichfits within the elongated loop 11.

Referring now to FIG. 2, details of the center piece will be described.Aa shown. this center piece comprises a body having an upper and lowerchannel formed on its top and bottom surfaces as indicated at 20 and 21respectively so as to define a general H- shape in cross section. Itwill be noted that the floor 22 of the upper channel 20 is convexbetween its exit end portions 23 and 24. This concave shape accommodatesthe general curvature of the central top portion of the elongated loopwhen the center piece is assembled within the loop as shown in H6. 1.

Referring to the front view of FIG. 3. the central top portions of theloop are indicated at 11d and lle in side-by-side relationship withinthe upper channel of the center piece 19. lt will be noted in this viewthat these portions exiting from the upper channel in the center pieceare jogged slightly as at 25 and 26 so that the further end portions ofthe outer bow lie in a plane passing between the upper portions of theelongated loop to include the line of contact indicated at 27 of theportions in side-byside relationship. This plane is per pendicular tothe plane of the drawing of FIG. 3.

Referring now to H6. 4. further details of the structure will beevident. As shown. the ends of the elongated loop designated 11a and 11hextend beyond the exit end portions 23 and 24 of the upper channel inthe center piece 19. Further. it will be noted that the convexconfiguration of the floor of the channel accommodates in surfacecontact the general curvature of this upper central portion of theelongated loop as described heretofore.

In FIG. 4, the securement of the central portion of the inner bow 14designated 28 to the central underside portion of the elongated loop llcis shown at 29 and as stated may constitute silver solder. It will alsobe clear that these respective portions lie one above the other withinthe lower channel of the center piece 19 in such a manner that the lowerside walls of this lower channel will eclipse the soldered connection asin the view of FIG. I.

The foregoing physical arrangement will also be clear from FIG. 5wherein the side-by-side upper loop portions [Id and 111: within theupper channel 20 of the center piece 19 is shown and the one above theother position of the lower central portion of the loop and centralportion of the inner bow 11c, and 28 respectively within the channel 21is shown.

The width ofthe lower channel 21 of the center piece 19 as shown in FIG.Sis such that the plane ofthe inner bow 14 can be adjusted to form adesired angle with the plane of the outer bow prior to soldering to thelower loop portion of the outer bow Thus. in assembling the device. theinner bow may be positioned as indicated by the dotted lines at 14'. lnthis example, the plane of the inner bow forms an angle below the planeof the outer bow. However. the plane of the inner bow could form asimilar angle above the plane of the outer bow if desired. Once asuitable relationship has been established. the parts are soldered asdescribed and the center piece then attachedOPERATlON Referringspecifically to FIG. 4. the manner in which the described structurelessens the risk of breaking of the outer bow or disconnection of theouter bow from the inner how will become evident. As shown in FIG. 4,when the outer ends of the outer bow 10 are bent or flexed inwardly asoften occurs. the portions of the upper loop 11d and lle at the pointsthey pass from the exit ends of the upper channel will bear down on thechannel floor surface portions adjacent these ends. These portions areindicated at 23 and 24 in FIG. 2 and serve as fulcrum surfaces for theouter bow portions. These fulcrum surfaces in addition to the end loopportions llu and 11b of the elongated loop. which portions as describedare spaced from the exit ends ofthe center piece. distributes the stressalong the end loop portions in such a manner that large stressconcentrations at any one point are avoided. Thus. it will be understoodthat the upper loop portions are simply resting in the upper channel andare free to move therein and rock on the convex surface in such a mannerto effect the desired stress distribution. The end loop portions 11a andllb themselves can circumferentially expand as necessary to accommodatebending movements Under bending of the outer extending ends of the outerbow inwardly. the loop portions and central top portions will assume thepositions illustrated in dotted lines in FIG. 4 wherein the fulcrumaction will be evident. Because the flexing is taken up along asubstantial distance of the end loops. there is very little stresscommunicated to the soldered portion 29in the lower channel of thecenter piece. Thus the risk of breakage is minimized.

From the foregoing description. it will be evident that the center piecereally serves a dual function. First. it will provide the desiredfulcrum surfaces to distribute stress in cooperation with the end loopportions. Second, it serves to-eclipse and protect the soldered connection of the inner bow to the under side central por tion of theelongated loop of the outer bow.

The foregoing basic feature in combination with the further features ofrounding off the extreme ends of the respective bows results in agreatly improved orthodontic face bow. The outer and inner bowsthemselves will normally comprise stainless steel wire and thus tarnishing of these portions is minimal. By providing the half loops in theouter stainless steel wire portions of the inner bow 14 as described toserve as stops. the presence of silver solder is avoided and thus theassociated problems of tarnishing are avoided. With respect to thesingle silver solder connection at the central portion of the bows. asdescribed the center piece eclipses and protects this connection so thatan overall esthetically pleasing device as well as an hygienic deviceresults.

What is claimed is:

1. An orthopedic face bow comprising. in combination:

a. an outer bow member defined forming an elongated loop at its centralportion;

b. an inner bow having its central portion secured to a centralunderside portion of said elongated loop; and.

c. a rigid centerpiece having a lower channel with a floor portionpassing through said elongated loop. the central portion of the innerbow and lower central portion of the loop lying in said channel so thatthe lower side walls eclipse the securement portion of the inner bow tothe outer bow the upper surface of said center piece defining theopposite side of the floor of said lower channel. including portionsservicing as fulcrum surfaces when the extending ends of the outer boware flexed inwardly.

2. An orthopedic face bow comprising. in combination:

a. an outer bow member defining an elongated loop at its central portionand terminating at its outer ends in integrally formed hooks;

b. an inner bow member having a central portion soldered to a centralunderside portion of said elongated loop; and

c. a center piece comprised of a body having an upper and lower channelformed on its top and bottom surfaces respectively so as to define ageneral Hshape in cross section. the upper portions of said elongatedloop lying in the upper channel in sideby-side relationship and thelower portion of the loop and a central portion of the inner bow memberlying in said lower channel. one above the other, the lower side wallsof said lower channel eclipsing the soldered connection of the inner bowto the loop. the end loop portions of the loop ex tending beyond theends of the channels in the center piece to provide flexibility andaccommodate bending of the outer bow, the floor of the upper channel ofsaid center piece adjacent the exit ends of the channel defining fulcrumsurfaces for the respective upper loop portions when bending occurs sothat stress in the loop is distributed about said end loop portions tominimize the risk of breaking of the outer bow and breaking its solderedconnection to said inner bow 3. A face bow according to claim 2, inwhich the floor of said upper channel is convex between its exit ends toaccommodate the general curvature of the central top portion of theelongated loop and increase the area of said fulcrum surfaces.

4. A face bow according to claim 2, in which said (ill inner bow memberincludes half loops formed near its outer ends to serve as stops, theposition along the bow at which the half loops are formed beingselectable thereby enabling the stop positions to be adjusted.

5. A face bow according to claim 2, in which the ex treme ends of theouter and inner bows are all radiuscd to avoid the presence of anysharp. jagged points.

6. A face bow according to claim 2. in which portions of the outer loopexiting from the upper channel in the center piece are jogged slightlyso that the further end portions of the outer bow lie in a plane passingbetween said upper portions of said elongated loop to include the lineof contact of the portions in side-by-side relationship.

7. A face bow according to claim 2, in which the width of the lowerchannel of said center piece is such that the plane of the inner bow canbe adjusted to form a desired angle with the plane of the outer bowprior to soldering to the underside central loop portion of the outerbow and insertion within said lower channel.

1. An orthopedic face bow comprising, in combination: a. an outer bowmember defined forming an elongated loop at its central portion; b. aninner bow having its central portion secured to a central undersideportion of said elongated loop; and, c. a rigid centerpiece having alower channel with a floor portion passing through said elongated loop,the central portion of the inner bow and lower central portion of theloop lying in said channel so that the lower side walls eclipse thesecurement portion of the inner bow to the outer bow the upper surfaceof said center piece defining the opposite side of the floor of saidlower channel, including portions servicing as fulcrum surfaces when theextending ends of the outer bow are flexed inwardly.
 2. An orthopedicface bow comprising, in combination: a. an outer bow member defining anelongated loop at its central portion and terminating at its outer endsin integrally formed hooks; b. an inner bow member having a centralportion soldered to a central underside portion of said elongated loop;and c. a center piece comprised of a body having an upper and lowerchannel formed on its top and bottom surfaces respectively so as todefine a general H-shape in cross section, the upper portions of saidelongated loop lying in the upper channel in side-by-side relationshipand the lower portion of the loop and a central portion of the inner bowmember lying in said lower channel, one above the other, the lower sidewalls of said lower channel eclipsing the soldered connection of theinner bow to the loop, the end loop portions of the loop extendingbeyond the ends of the channels in the center piece to provideflexibility and accommodate bending of the outer bow, the floor of theupper channel of said center piece adjacent the exit ends of the channeldefining fulcrum surfaces for the respective upper loop portions whenbending occurs so that stress in the loop is distributed about said endloop portions to minimize the risk of breaking of the outer bow andbreaking its soldered connection to said inner bow.
 3. A face bowaccording to claim 2, in which the floor of said upper channel is convexbetween its exit ends to accommodate the general curvature of thecentral top portion of the elongated loop and increase the area of saidfulcrum surfaces.
 4. A face bow according to claim 2, in which saidinner bow member includes half loops formed near its outer ends to serveas stops, the position along the bow at which the half loops are formedbeing selectable thereby enabling the stop positions to be adjusted. 5.A face bow according to claim 2, in which the extreme ends of the outerand inner bows are all radiused to avoid the presence of any sharp,jagged points.
 6. A face bow according to claim 2, in which portions ofthe outer loop exiting from the upper channel in the center piece arejogged slightly so that the further end portions of the outer bow lie ina plane passing between said upper portionS of said elongated loop toinclude the line of contact of the portions in side-by-siderelationship.
 7. A face bow according to claim 2, in which the width ofthe lower channel of said center piece is such that the plane of theinner bow can be adjusted to form a desired angle with the plane of theouter bow prior to soldering to the underside central loop portion ofthe outer bow and insertion within said lower channel.